Apparatus for attaching a flexible bag to a container body

ABSTRACT

A plurality of fingers contract into a generally elliptical pattern and expand into a generally cylindrical pattern to present to a container body an expanded mouth of a flexible bag. With the upper flange of a container body slightly above the free ends of the expanded fingers the fingers are collapsed close to the outside of the container body below the flange to allow stripping of the bag from the fingers. To facilitate gripping of the bag with limited finger area engagement, each of the fingers has a raised rib for engaging the bag. The change in the pattern of the fingers is effected through linkage. The linkage includes four rocker arms with pairs of the rocker arms pivotally mounted to a base on diametric opposite sides of an opening in the base. Each of two axially aligned actuator shafts drive two of the rocker arms through drive links. The actuator shafts are at right angles to the plane of the axes of the pivots. A pair of coordinating links for each pair of rocker arms carries one of the fingers. Each rocker arm and each actuator shaft carries a finger. The pivotal connections of the linkage elements is such that the elliptical to cylindrical finger pattern develops when the actuator shafts are pulled away from each other.

United States Patent n 1- Marhold V 111 3,710,693 [451 Jan. 16, 1973 [54] APPARATUS FOR ATTACHING A FLEXIBLE BAG TO A CONTAINER BODY [58] Field of Search .93/36.01, 8 WA, 35 VL, 59 CE, 93/77 CL, 84 FF; 53/175; 29/450, 235

[56] References Cited UNITED STATES PATENTS 3,523,492 8/1970 Bruce et a1. ..93/36.01 3,266,390 8/1966 Carpenter, .lr. 2,152,941 4/1939 Wilcox ..93/59 CE Primary Examiner-Andrew R. .luhasz Assistant Examiner-James F. Coan Attorney-Christie, Parker & Hale [5 7] ABSTRACT A plurality of fingers contract into a generally elliptical pattern and expand into a generally cylindrical pattern to present to a container body an expanded mouth of a'flexible bag. With the upper flange of a container body slightly above the free ends of the expanded fingers the fingers are collapsed close to the outside of the container body below the flange to allow stripping of the bag from the fingers. To facilitate gripping of the bag with limited finger area engagement, each of the fingers has a raised rib for engaging the bag.

The change in the pattern of the fingers is effected through linkage. The linkage includes four rocker arms with pairs of the rocker arms pivotally mounted to a base on diametric opposite sides of an opening in the base. Each of two axially aligned actuator shafts drive two of the rocker arms through drive'links. The actuator shafts are at right angles to the plane of the axes of the pivots. A pair of coordinating links for each pair of rocker arms carries one of the fingers. Each rocker arm and each actuator shaft carries a finger. The pivotal connections of the linkage elements is such that the elliptical to cylindrical finger pattern develops when the actuator shafts are pulled away from each other.

21 Claims, 8 Drawing Figures PATENTEBJAH 1s m SHEET 3 0F 3 APPARATUS FOR ATTACHING A FLEXIBLE BAG TO A CONTAINER BODY BACKGROUND OF THE INVENTION The present invention relates in general to the fabrication of containers of the pressurized type, and, more in particular, to an apparatus for attaching a flexible bag to a container body.

Pressurized containers for dispensing various products are very popular. These containers employ a propellant to pressurize a product. Product is typically discharged through the hand actuation of a dispensing valve. One of the most effective pressurized containers is described in U.S. Pat. No. 3,393,842 to John K. Bruce. The pressurized container described in this patent employs a flexible bag or tube within a container body. Propellant urges against one side of the bag to pressurize product on the other side of the bag. When a valve is actuated, product is discharged from the force of the propellant. The flexible bag is attached to the container body by stretching the mouth of the bag over the top seaming flange of the body and down along the outside of the body. A dispenser dome is double seamed into place with bag material interposed between body and dome material.

Because of the type of films used for bags in bag-incan type dispensers, the amount of stretching which a bag can sustain during its attachment to a container body is not great before the bag tears or plastically deforms.

While the mouth of the bag is expanded for its attachment to the container body, obviously the container body must be placed within the mouth of the bag.

In U.S. Pat. No. 3,523,492 to John K. and Roger K. Bruce an apparatus and method for attaching flexible bags to container bodies is. described. The patent describes an apparatus which employs a plurality of cam-actuated fingers which are capable of radial movement back and forth between a contracted position and an expanded position. in the contracted position the fingers are in position to receive a bag. In the expanded position the bag's mouth has been expanded for ultimate receipt on the outside of a container body.

The apparatus described in the Bruce et al. patent has proven very effective. However, in some applications the circular array of contracted fingers has proven troublesome because of difiiculties in placing the mouths of bags over the contracted fingers in the first place. Also, there has developed a requirement for not having a relatively long length of bag material stretched over the outside of the container bodies.

SUMMARY OF THE INVENTION The present invention provides an apparatus for expanding the mouth of a flexible bag for the bags attachment to the end of a container body. The apparatus is characterized by a plurality of fingers capable of movement between a contracted position where the fingers lie in a generally elliptical array to an expanded position where the fingers lie in a generally right cylindrical array. In preferred form, each of the bag engaging fingers has an outer circumferentially disposed, radially extending rib for facilitating a tight engagement between the bag and the finger. The ribbed fingers admit to a shorter length of engagement between the mouth of the bag and the fingers with the result that there is not a relatively large length of bag extending down the outside of a container body. Consequently, the length of bag lying on the outside of the body can be made just sufficient to form the double seam construction described in detail in U.S. Pat. No. 3,393,842.

With the elliptical array of the fingers in their collapsed position, it is much easier to place a bag over the fingers as, for example, by a pair of vacuum fingers. Another way of saying the same thing is that with the elliptical array the fingers have a periphery quite a bit more like the unexpanded mouth of tubular stock or bags used in the fabrication of bag-in-can type dispensers of the type noted here.

A specific form of the present invention contemplates an apparatus for attaching a flexible bag to a right cylindrical container body over a seaming flange of the body. The apparatus includes a base, a plurality of individual fingers and means for expanding and contracting the fingers between an expanded and contracted position. The fingers are disposed on the base to present in their expanded position bag engaging surfaces which define a substantially continuous right cylindrical surface interrupted only by small spaces between the fingers. This cylindrical array is for holding the expanded mouth of the bag for subsequent placement over the end of a container body. The fingers in their expanded position also present a passage for receipt of a container body within them with the fingers being between the container body and the expanded mouth of the bag. The fingers in their contracted position present a generally elliptical array. The periphery of the bag engaging surfaces of the fingers in the elliptical array is substantially less than the periphery of the bag engaging surfaces in their expanded position. The limited periphery in the elliptical array is tofacilitate the receipt of the mouth of the bag over the fingers.

It is also preferred that the elliptical array be such that the long axis of the ellipse is shorter than the diameter of the cylinder defined by the bag engaging surfaces of the fingers in their expanded position. This facilitates the insertion of the mouth of the bag over the collapsed fingers.

In its specific form, the fingers of. the present invention are carried by linkage in the form of two pairs of rocker arms, each pair being pivotally mounted to a base on diametrically opposite sides of an opening through the base. Each rocker arm is coupled to an actuator shaft through an associated drive link. There are two actuator shafts axially aligned with respect to each other at right angles to the plane of the base pivot axes of the rocker arms. Each actuator shaft drives one rocker arm of each pair of rocker arms. Coordinating links of each pair of rocker arms carry a finger. Each rocker arm carries a finger and each actuator shaft carries a finger, the latter through a yoke. The facing periphery of each element of the linkage is such that in the collapsed finger position the fingers nest together in close proximity to each other.

These and other features, aspects and advantages of the present invention will become more apparent'from the following description, appended claims and drawings.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a bottom plan view of a preferred form of the applicator head of the present invention illustrating its fingers in an expanded cylindrical array;

FIG. 2 is a view taken along line 2-2 of FIG. 1;

FIG. 3 is a bottom plan view of the applicator head of FIG. 1 showing its fingers in a collapsed, generally elliptical array;

FIG. 4 is a fragmentary view in elevation showing the detail of rocker arm pivotal connection to the base of the apparatus;

FIG. 5 is a fragmentary view illustrating the receipt of the mouth of a bag by the fingers in the latters collapsed elliptical array;

FIG. 6 illustrates the mouth of the bag expanded by the fingers and a dispenser or container body disposed within the expanded fingers;

FIG. 7 illustrates the relaxation of the fingers against the outside of a dispenser body to facilitate the stripping of the bag from the fingers and the ultimate elastic contraction of the mouth of the bag around the outside surface of a dispenser body and over the seaming flange of the body; and

FIG. 8 is a schematic view illustrating a typical means of actuating the applicator head of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the first three Figures the preferred form of the tube or bag applicator of the present invention is illustrated. The applicator includes a base 10 which has a central opening 12 through it for receiving the body of a dispenser onto which a flexible bag is to be attached. The base supports rocker arm pairs 14 and 16. The first of these rocker arm pairs includes individual first and second rocker arms 18 and 20, respectively. The second of the rocker arm pairs also includes first and second individual rocker arms indicated by reference numerals 22 and 24, respectively.

The first and second rocker arms of the first rocker arm pair are pivotally mounted to the base through a pivot pin 26. Similarly, the rocker arms of the second rocker arm pair are pivotally mounted to the base through a pivot pin 28. It should be noted that the pivotal axis defined by the pivot pins, and hence the axis around which each of the rocker arms is capable of pivoting or rotating, lies in a plane which also contains a central axis 30 corresponding to the longitudinal axis of the container or body. Stated in slightly different language, each of the rocker arms of each pair of rocker arms is capable of rotating about an axis which lies in a plane common to the rotational axis of its complementary pair of rocker arms and which contains the longitudinal axis of the container body onto which a bag is to be attached.

The rocker arms are actuated by a pair of actuator shafts 32 and 34. These actuator shafts have coaxial axes which pass through central axis 30 and which are normal to the central axis. Each actuator shaft is journaled for linear movement toward and away from the central axis in linear bearings. The linear bearing for actuator shaft 32 is indicated by reference numeral 36 while the linear bearing for actuator shaft 34 is indicated by reference numeral 38. The linear bearings in turn are held in place on base 10 through bearing blocks 40 and 42 for linear bearings 36 and 38, respectively. The bearing blocks are attached to the base through male fasteners 44. Bearing block 40 is accurately indexed with respect to central axis 30 through a spline 45 of the bearing block residing in a cooperating slot 47 in base 10. Bearing block 42 is indexed in the same manner.

Yokes 46 and 48 are attached to actuator shafts 32 and 34, respectively, on their inner ends through male fasteners 50.

Four drive links, indicated by reference numerals 52, 54, 56 and 58, are provided to drive the rocker arms through the yokes. These drive links. specifically, are

. attached through pivot pins 60 on their inner ends to the yokes and through pivot pins 62 on their outer ends to the rocker arms. The axes of inner pivot pins 60 all lie in a common circle, the center of which corresponds to central axis 30. Similarly, the axis of the outer pivot pins also lie on a common circle, the center of which corresponds to the central axis. While the pivot pins move in and out with respect to the central axis during finger contraction and expansion, the correspondence of distance between the central axis and the inner and outer pivot pins is maintained throughout the positional changes of the pivot pins.

A pair of coordinating links 64 and 66 are provided for first and second rocker arms 18 and 20 of rocker arm pair 14. These coordinating links are pivotally connected to their rocker arms through pivot pins 68 and 70. These coordinating links are also pivotally connected to a finger mount 72 through pivot pins 74 and 76. A similar pair of coordinating links 78 and 80 are provided for first and second rocker arms 22 and 24 of rocker arm pair 16. These coordinating links are mounted to first and second rocker arms 22 and 24 through pivot pins 82 and 84 and are mounted to a finger mount 86 through pivot pins 88 and 90. The axis of pivot pins 74, 76, 88 and 90 all lie on a common circle, the center of which is central axis 30. In like manner the axes of pivot pins 38, 70, 82 and 84 also lie on a common circle, the center of which lies on central axis 30.

Thus all the pivot points for the linkage of the applicator of the present invention all lie on circles which change in diameter but which always have central axis 30 as their center.

Fingers 92 and 94 are provided at the inner ends of yokes 46 and 48, respectively. As is most readily apparent from FIG. 2, finger 92 is attached to yoke 46 through a pair of screws 96 which pass through a mounting flange 98 of the finger. The mounting flange of the finger is received in a recess in the yoke. As previously mentioned, the yoke itself is attached to its actuator shaft through male fasteners 50 and bears against the actuator shaft along a flat interface 100 between the two. Yoke 46 has ears 102 and 104 to the rear of a nose portion 106. The nose portion provides the mounting for finger 92. The nose has a taper which progressively diverges from the finger to meet the ears.

Yoke 48 has a configuration identical to yoke 46 except that the yokes face each other. As such, yoke 46 will not be described in detail.

Rocker arm pairs 14 and 16, as previously mentioned, are pivotally connected through pivot pins to base 10. This is shown explicitly in FIG. 4 for rocker arm pair 16. The overlapping relationship between two cooperating rocker arms 22 and 24 is also shown in this Figure. Bearings 108 and 110 are provided for a low friction pivot.

In any event, rocker arm 22 extends from its pivotal connection to base to its pivotal connection at pin 62 to drive link 54. Intermediate these two pivot points of rocker arm 22 is an interior facing foot 112 which acts as a finger mount for a finger 114. An interior facing foot 116 is provided for cooperating rocker arm 24 which also acts as a mount for a finger l 18. Similarly, in rocker arm pair 14, an interior facing foot 120 and an interior facing foot 122 for rocker arms 18 and 20, respectively, provide finger mounts for fingers 124 and 126, respectively. The depending feet of the rocker arms, of course, follow the rocking motion of the arms between the open and closed positions, as seen explicitly in FIGS. 1 and 3.

Finger mounts 72 and 86 also have fingers which are indicated by reference numerals 128 and 130, respectively. The fingers of the rocker arms and of finger mounts 72 and 86 are attached in a manner essentially identical to the manner in which finger 92 is attached to nose portion 106 of yoke 46. Consequently, an explicit description of each finger's attachment to its mount or foot, as the case may be, will not be undertaken.

With specific reference again to the elevational view of the bag applicator of the present invention, FIG. 2, it is seen that the fingers extend upwardly in opening 12 to the top of base 10. A bag engaging rib 132 is provided proximate the top of each of the fingers to aid in keeping a bag on the fingers with a relatively small amount of engagement area between the fingers and the bag. These ribs in aggregate and in the expanded position of the fingers describe a circle, interrupted by the space between fingers, which lies in a plane normal to central axis 30. As is seen to best effect in FIG. 1, the outer radial surfaces of the fingers are sections of the surface of a common right cylinder having as an axis central axis 30. These outer surfaces are, of course, the bag engaging surfaces of the fingers, one of which is referred to expressly by reference numeral 134 in FIGS. 1 and 2. The inner surfaces of the fingers are also longitudinal sections of a right cylinder, the axis of which is central axis 30. One of these concave inner surfaces is indicated by reference numeral 136. These surfaces collapse against the unbent, longitudinally straight, right cylindrical surface of the container body to which a bag is to be attached.

With reference to the right-hand side of FIG. 2, it is seen that drive link 56 and coordinating links 80 underlie rocker arm 24 which in turn underlies a portion of opening 12. The longitudinal orientation of the other rocker arms, drive links and coordinating links is the same.

With reference to FIG. 3, it can be seen that the somewhat unusual interior peripheries of the rocker arms and exterior periphery of the yokes is necessary for proper contraction of the linkage into a tightly compacted nest. This amount of contraction generates an elliptical array of the fingers which has a very'short minor axis with respect to the major axis. In short, for the maintenance of the fingers and linkage in a compact elliptical array, it is necessary to have conforming peripheries for the various parts.

Specifically and with initial reference to the fingers in their expanded array, FIG. 1, the interior periphery of rocker arm 24 beginning in the vicinity of pivot 62 generally parallels a line between the axis of pivot 62 and the axis of pivot 26 for a distance and then turns inwardly towards opening 12 in a generally circular curve to meet the base of the mounting flange for finger 118. These two sections of the periphery are indicated by reference numerals 135 and 137, respectively. From the base of the mounting flange, the periphery extends at 138 generally radially inward toward central axis 30 to meet finger 118 proper. On the side of foot 116 closest to the line extending through the axes of pivots 26 and 28 the periphery begins generally radially but very soon progresses into a generally circular curve 140 which extends under coordinating link 80 and merges into the radiused end of the rocker arm. The conforming periphery of yoke 48 taken from finger 94 begins with a periphery which extends generally radially from central axis 30 at 142 to the ear on which drive link 56 is pivotally attached. The periphery of the ear is generally circular with a curvature smaller than the corresponding curvature of the periphery 137 of the rocker arm facing the ear adjacent foot 116. The ears periphery is indicated by reference numeral 144. Slightly to the rear of a line through the pivot axes of pivots 60 for yoke 48 the periphery of this yoke extends as a straight line 146 away from central axis 30 and towards the axis of actuator shaft 34.

With emphasis again to FIG. 3 it is seen that rocker arm 24 in its collapsed position has its pivot 62 drawn in towards the axis of actuafor shaft 34. This is the reason for the slant of the periphery of yoke 48 to the rear of pivots 60. It will also be noted that foot 116 and the nose of yoke 48 get very close to each other. Hence the reason for the shape of their facing peripheries. And mount 86 in the contracted position shown in F IG. 3 nestles snugly in a pocket defined by the facing peripheries 148 and 150 of the rocker arms surrounding the mount. The mount's flanks 152 are tapered to converge towards finger 128 to accommodate the close proximity of the facing peripheries of the adjoining rocker arms.

The periphery for the remaining elements of the linkage is essentially the same as that just described and will not be described further.

The operation of the tube applicator of the present invention will be described with particular reference to F 16$. 5 through 8. initially, and with reference to FIG. 5, the fingers are shown looking from the right in FIG. 3 and the fingers are in their contracted, generally elliptical array. ln this position they present a very limited periphery. The mouth of a bag 154 to be attached to the body of a container is placed over the contracted fingers. For this purpose the bag can be preformed and its mouth initially opened slightly as by opposed vacuum fingers and placed over the contracted fingers of the applicator. The bag, because of its manufacture or because of how it is stored, may have a flat set in which case the long dimension of the mouth of the bag would be oriented to correspond tothe major axis of the elliptical fingers.

After the bag has been placed over the fingers the fingers are then expanded into their expanded position as shown in FIGS. 1 and 6. In this position the bag engaging surfaces of the fingers generally fall on the surface of an imaginary right cylinder. The diameter of this cylinder is larger than the unstretched perimeter of the inside of the bags mouth. Ribs 132 of the fingers press tightly against the inside of the bags mouth to tightly grip the bag. The balance of the bag engaging surfaces of the fingers also press tightly against the in side of the bags mouth. It should be noted that the amount of longtidinal engagement between the inside of the bags mouth and the bag engaging surfaces of the fingers need not be very great because of ribs 132. In short, the ribs provide a gripping power sufficient to allow foreshortening the amount of longitudinal engagement between the fingers and the inside of the bag without fear of the bag slipping off the fingers. Consequently the amount of bag material on the outside of a container body can be tailored exactly to fit into the double seam of U.S. Pat. No. 3,393,842.

After the fingers have been expanded inside the mouth of the bag and the mouth duly expanded, a container body 156 is placed between them. For this purpose the apparatus described in U.S. Pat. No. 3,523,492 to John K. Bruce et al. will suffice. In any event, an upper seaming flange 158 of the container body is presented slightly above the tops of the expanded fingers. As shown in FIG. 7, the fingers are then contracted into close proximity with the unbent portion of the outside of the body to allow the bag to contract against the seaming flange. The fingers are not brought into tight engagement with the container body.

Next, the container body is advanced upwardly with respect to the fingers to pull with it the bag mouth and slip the mouth off the fingers. For this purpose the bag's contracted engagement against the seaming flange is scope of the appended claims should not, however, necessarily be limited to the foregoing description.

What is claimed is:

1. An improved applicator for attaching flexible bags to a container body comprising: I

a. a base having an opening for receiving a container body, the opening having a central axis;

b. a plurality of fingers coupled to the base, each having a bag engaging surface facing away from the central axis and extending parallel to the central axis; and

. means for moving the fingers between a contracted position and an expanded position, the fingers in their contracted position generally defining an elliptical array and in their expanded position generally defining a right cylindrical array, the right cylindrical array having a periphery along the bag engaging surfaces greater than the periphery along the bag engaging surfaces in the elliptical array.

2. The improved applicator claimed in claim 1 wherein:

each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers.

3. The improved applicator claimed in claim 1 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of sufficient to hold the bag with the container body.

After the stripping operation the fingers are once again expanded to enable the discharge of the container body with its bag attached to it from the applicator head.

It is preferred that the bag be drawn inside the container body as described in U.S. Pat. No. 3,523,492 after the fingers have been relaxed.

An arrangement which will enable the operation of the fingers of the applicator head is shown schematically in FIG. 8. In this schematic depiction, a pair of pneumatic cylinders 160 and 162 are provided to actuate actuator shafts 32 and 34. A control valve 164 between a source of air 166 and the pneumatic cylinders is provided. One chamber of the control valve is in series communication with a side of each of the pneumatic cylinders which tends to force the actuator shafts outwardly in F IG. 3. This outward movement of the actuator shafts produces the opening of the fingers into their generally cylindrical orientation of FIG. '1. The other chamber of the valve is in communication with the sides of the pneumatic cylinders which tends to force the actuator shafts inwardly into their retracted, generally elliptical array, that is, going from the FIG. 1 configuration to the FIG. 2 configuration. The valve can be a solenoid actuated and in circuit with appropriate circuitry to automate the operation, if desired.

The present invention has been described with reference to a preferred embodiment. The spirit and which is the central axis.

4. The improved applicator claimed in claim 1 wherein each of the fingers has an inner surface which generally faces and parallels the central axis, the inner surfaces having a concave curvature of about the same as the curvature of the outside of a container body.

5. The improved applicator claimed in claim 4 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregatein the expanded position being on the circumference of a circlethe center of which is the central axis.

6. An improved applicator for attaching a flexible bag around the outside of an end of a generally cylindrical container body comprising:

a. a base having an opening therein for receiving the container body;

a plurality of fingers on the base around the opening, each finger having a bag engaging surface facing away and paralleling from a central axis of the fingers; and

. linkage means coupling the fingers together for movement between a contracted position and an expanded position, the fingers in their contracted position being in a generally elliptical array, the fingers in their expanded position being in a generally right cylindrical array having a periphery along the bag engaging surfaces greater than the periphery along the bag engaging surfaces in the elliptical array.

7. The improved applicator claimed in claim 6 wherein the linkage means includes:

a. two pairs of rocker arms of two rocker arms each, each pair of rocker arms being pivotally connected to the base in spaced relation to one another;

b. a pair of spaced apart yokes;

c. means connecting the yokes to the rocker arms such that with movement of the yokes towards each other the fingers move towards their contracted position and with movement of the yokes away from each other the yokes move toward their expanded position.

8. The improved applicator claimed in claim 7 wherein:

a line through the pivotal connection of the rocker arms to the base and the line of movement of the yokes are orthogonal with respect to each other and intersect at the central axis.

9. The improved applicator claimed in claim 8 wherein the means connecting the yokes and the rocker arms includes a drive link for each rocker arm between it and the proximate yoke.

10. The improved applicator claimed in claim 9 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of which is the central axis.

11. The improved applicator claimed in claim 7 wherein one of the fingers is at each end of the major axis of the elliptical array and the distance between the bag engaging surfaces of such two fingers in the elliptical array being less than the corresponding'distance of the same two fingers in the cylindrical array.

12. An improved applicator for attaching a flexible bag to a container body over the top thereof and in stretched elastic contact therewith comprising:

a. a base having a hole therein for receipt of a container body;

b. a plurality of fingers each having a bag engaging surface which parallels a central axis which axis corresponds to the axis of a container body within the hole in the base; and

c. linkage means connecting the fingers and the base for movement of the fingers between an expanded and a contracted position, the linkage means including two rocker arm pairs, each rocker arm pair having two rocker-arms, each rocker arm of a first of the rocker arm pairs being pivotally connected to the base outside the hole on a first common pivot, each rocker arm of a second of the rocker arm pairs being pivotally connected to the base outside the hole on a second common pivot, a plane through the pivot axes of the rocker arm pivots containing the central axis, a pair of spaced apart yokes mounted to the base for rectilinear motion toward and away from each other along a line of movement passing through the central axis and orthogonal to -the plane of the rocker arm pivots, drive links pivotally connecting each rocker arm to a corresponding yoke to control movement thereof between the contracted finger .position and the expanded finger position, one each of the fingers being mounted on each of the rocker arms and yokes, one each of the fingers being carried by each of the rocker arm pairs proximate the rocker arm pivots in face-to-face relationship with each other, the fingers in their expanded position having their bag engaging surfaces falling on a common right cylinder, the axis of which is the central axis, and the fingers in their contracted position defining an elliptical array with the major axis of the elipse being between the two fingers, each of which is carried by one of the rocker arm pairs.

13. The improved applicator claimed in claim 12 wherein a finger mount is provided for each of the two fingers each of which is carried by one of the rocker arm pairs, the finger mounts being pivotally carried by their respective rocker arms.

14. The improved applicator claimed in claim 13 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of which is the central axis.

15. An apparatus for attaching a flexible bag to a container body comprising:

a. a base having an opening therethrough for receipt of a container body with the longitudinal axis of each container body lying on a central axis of the opening;

b. a first and a second actuator shaft coaxially mounted on the base for rectilinear movement along their axes towards and away from each other and the central axis, the axes of the actuator shafts lying in a first plane of symmetry containing the central axis, the axes of the actuator shafts also being at right angles to the central axis;

c. a first and a second pivot symmetrically disposed in spaced relationship to each other on either side of the first plane of symmetry, each pivot having a pivot axis parallel to the central axis and at a right angle to the axes of the actuator shafts, the first and second pivot axes lying in a second plane of symmetry which contains the central axis;

d. a first pair of first and second rocker arms pivotally mounted on the first pivot and being symmetrical to each other about the second plane of symmetry;

e. a second pair of first and second rocker arms pivotally mounted on the second pivot and being symmetrical to each other about the second plane of symmetry;

f. the first and second pair of rocker arms being symmetrical to each other about the first plane of symmetry;

g. a first drive link for each of the first rocker arms, each first drive link being pivotally connected to its associated rocker arm and the first actuator shaft;

h. second drive links for each of the second rocker arms, each second drive link being pivotally connected to its associated rocker arm and the second actuator shaft;

i. a first coordinating link for each of the first rocker arms, each first coordinating link being pivotally connected to its associated rocker arm proximate such rocker arm's mounting to its pivot;

j. a second coordinating link for each of the second rocker arms, each second coordinating link being pivotally connected to its associated rocker arm proximate such rocker arm s mounting to its pivot;

. the first and second coordinating links associated with the first pivot being symmetrical about the second plane of symmetry and defining a first coordinating link pair, the first and second coordinating links associated with the second pivot being symmetrical about the second plane of symmetry and defining a second coordinating link pair;

1. a bag engaging finger carried by each of the rocker arms, each of the actuator shafts, and each pair of coordinating links;

111. the pivotal interconnection of the actuator shafts, drive links, rocker arms and coordinating links being such as to define in an expanded position of the actuator shafts a bag engaging finger geometry wherein radially extending outer bag engaging surfaces of the fingers lie along the surface of an imaginary right cylinder having a longitudinal axis on the central axis and in a contracted position of the actuator shafts to define an elipse with the long axis of the elipse being along the second plane of symmetry and the short axis of the elipse being along the first plane of symmetry.

16. The apparatus claimed in claim 15 wherein the pivotal connection of each of the coordinating links to its rocker arm being such that the distance between the bag engaging surfaces of the fingers associated with the coordinating links is foreshortened in the contracted position of the actuator shafts with respect to the corresponding distance in the expanded position of the actuator shafts.

17. The apparatus claimed in claim 16 wherein a first and a second yoke are provided for the first and second actuator shafts, each yoke providing the finger mount for its actuator shafts finger and the pivotal connection base of its actuator shafts drive links.

18. The apparatus claimed in claim 17 wherein:

each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers.

19. The apparatus claimed in claim 17 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of which is the central axis.

20. The apparatus claimed in claim 19 wherein each of the fingers has an inner surface which generally faces and parallels the central axis, the inner surfaces having a concave curvature of about the same as the curvature of the outside of a container body.

21. An apparatus for attaching a flexible bag to a right cylindrical container body comprising:

a. a base;

b. a plurality of individual fingers disposed on the base for movement both ways between an expanded position and a contracted position, each of the fingers in its expanded position presenting an outer, bag engaging surface which cooperates with the bag engaging surfaces of the other fingers to define a surface array falling substantially on the surface of an imaginary right cylinder, the cylindrical array being for holding the expanded mouth of the bag for subsequent placement over the end of the container body, the fingers in their expanded position also presenting a passage for receipt of a container body within the fingers, the fingers in their contracted position presenting a generally elli tical arra the ri he of which is substanti lly less th an the p erl ph y of the bag engaging surfaces in their expanded position, the limited periphery elliptical array being to facilitate the receipt of the mouth of the bag over the fingers;

and means for expanding and contracting the fingers between their expanded and contracted positions.

# i i i i 

1. An improved applicator for attaching flexible bags to a container body comprising: a. a base having an opening for receiving a container body, the opening having a central axis; b. a plurality of fingers coupled to the base, each having a bag engaging surface facing away from the central axis and extending parallel to the central axis; and c. means for moving the fingers between a contracted position and an expanded position, the fingers in their contracted position generally defining an elliptical array and in their expanded position generally defining a right cylindrical array, the right cylindrical array having a periphery along the bag engaging surfaces greater than the periphery along the bag engaging surfaces in the elliptical array.
 2. The improved applicator claimed in claim 1 wherein: each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers.
 3. The improved applicator claimed in claim 1 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of which is the central axis.
 4. The improved applicator claimed in claim 1 wherein each of the fingers has an inner surface which generally faces and parallels the central axis, the inner surfaces having a concave curvature of about the same as the curvature of the outside of a container body.
 5. The improved applicator claimed in claim 4 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of which is the central axis.
 6. An improved applicator for attaching a flexible bag around the outside of an end of a generally cylindrical container body comprising: a. a base having an opening therein for receiving the container body; b. a plurality of fingers on the base around the opening, each finger having a bag engaging surface facing away and paralleling from a central axis of the fingers; and c. linkage means coupling the fingers together for movement between a contracted position and an expanded position, the fingers in their contracted position being in a generally elliptical array, the fingers in their expanded position being in a generally right cylindrical array having a periphery along the bag engaging surfaces greater than the periphery along the bag engaging surfaces in the elliptical array.
 7. The improved applicator claimed in claim 6 wherein the linkage means includes: a. two pairs of rocker arms of two rocker arms each, each pair of rocker arms being pivotally connected to the base in spaced relation to one another; b. a pair of spaced apart yokes; c. means connecting the yokes to the rocker arms such that with movement of the yokes towards each other the fingers move towards their contracted position and with movement of the yokes away from each other the yokes move toward their expanded position.
 8. The improved applicator claimed in claim 7 wherein: a line through the pivotal connection of the rocker arms to the base and the line of movement of the yokes are orthogonal with respect to each other and intersect at the central axis.
 9. The improved applicator claimed in claim 8 wherein the means connecting the yokes and the rocker arms includes a drive link for each rocker arm between it and the proximate yoke.
 10. The improved applicator claimed in claim 9 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of which is the central axis.
 11. The improved applicator claimed in claim 7 wherein one of the fingers is at each end of the major axis of the elliptical array and the distance between the bag engaging surfaces of such two fingers in the elliptical array being less than the corresponding distance of the same two fingers in the cylindrical array.
 12. An improved applicator for attaching a flexible bag to a container body over the top thereof and in stretched elastic contact therewith comprising: a. a base having a hole therein for receipt of a container body; b. a plurality of fingers each having a bag engaging surface which parallels a central axis which axis corresponds to the axis of a container body within the hole in the base; and c. linkage means connecting the fingers and the base for movement of the fingers between an expanded and a contracted position, the linkage means including two rocker arm pairs, each rocker arm pair having two rocker arms, each rocker arm of a first of the rocker arm pairs being pivotally connected to the base outside the hole on a first common pivot, each rocker arm of a second of the rocker arm pairs being pivotally connected to the base outside the hole on a second common pivot, a plane through the pivot axes of the rocker arm pivots containing the central axis, a pair of spaced apart yokes mounted to the base for rectilinear motion toward and away from each other along a line of movement passing through the central axis and orthogonal to the plane of the rocker arm pivots, drive links pivotally connecting each rocker arm to a corresponding yoke to control movement thereof between the contracted finger position and the expanded finger position, one each of the fingers being mounted on each of the rocker arms and yokes, one each of the fingers being carried by each of the rocker arm pairs proximate the rocker arm pivots in face-to-face relationship with each other, the fingers in their expanded position having their bag engaging surfaces falling on a common right cylinder, the axis of which is the central axis, and the fingers in their contracted position defining an elliptical array with the major axis of the elipse being between the two fingers, each of which is carried by one of the rocker arm pairs.
 13. The improved applicator claimed in claim 12 wherein a finger mount is provided for each of the two fingers each of which is carried by one of the rocker arm pairs, the finger mounts being pivotally carried by their respective rocker arms.
 14. The improved applicator claimed in claim 13 wherein each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of which is the central axis.
 15. An apparatus for attaching a flexible bag to a container body comprising: a. a base Having an opening therethrough for receipt of a container body with the longitudinal axis of each container body lying on a central axis of the opening; b. a first and a second actuator shaft coaxially mounted on the base for rectilinear movement along their axes towards and away from each other and the central axis, the axes of the actuator shafts lying in a first plane of symmetry containing the central axis, the axes of the actuator shafts also being at right angles to the central axis; c. a first and a second pivot symmetrically disposed in spaced relationship to each other on either side of the first plane of symmetry, each pivot having a pivot axis parallel to the central axis and at a right angle to the axes of the actuator shafts, the first and second pivot axes lying in a second plane of symmetry which contains the central axis; d. a first pair of first and second rocker arms pivotally mounted on the first pivot and being symmetrical to each other about the second plane of symmetry; e. a second pair of first and second rocker arms pivotally mounted on the second pivot and being symmetrical to each other about the second plane of symmetry; f. the first and second pair of rocker arms being symmetrical to each other about the first plane of symmetry; g. a first drive link for each of the first rocker arms, each first drive link being pivotally connected to its associated rocker arm and the first actuator shaft; h. second drive links for each of the second rocker arms, each second drive link being pivotally connected to its associated rocker arm and the second actuator shaft; i. a first coordinating link for each of the first rocker arms, each first coordinating link being pivotally connected to its associated rocker arm proximate such rocker arm''s mounting to its pivot; j. a second coordinating link for each of the second rocker arms, each second coordinating link being pivotally connected to its associated rocker arm proximate such rocker arm''s mounting to its pivot; k. the first and second coordinating links associated with the first pivot being symmetrical about the second plane of symmetry and defining a first coordinating link pair, the first and second coordinating links associated with the second pivot being symmetrical about the second plane of symmetry and defining a second coordinating link pair; l. a bag engaging finger carried by each of the rocker arms, each of the actuator shafts, and each pair of coordinating links; m. the pivotal interconnection of the actuator shafts, drive links, rocker arms and coordinating links being such as to define in an expanded position of the actuator shafts a bag engaging finger geometry wherein radially extending outer bag engaging surfaces of the fingers lie along the surface of an imaginary right cylinder having a longitudinal axis on the central axis and in a contracted position of the actuator shafts to define an elipse with the long axis of the elipse being along the second plane of symmetry and the short axis of the elipse being along the first plane of symmetry.
 16. The apparatus claimed in claim 15 wherein the pivotal connection of each of the coordinating links to its rocker arm being such that the distance between the bag engaging surfaces of the fingers associated with the coordinating links is foreshortened in the contracted position of the actuator shafts with respect to the corresponding distance in the expanded position of the actuator shafts.
 17. The apparatus claimed in claim 16 wherein a first and a second yoke are provided for the first and second actuator shafts, each yoke providing the finger mount for its actuator shaft''s finger and the pivotal connection base of its actuator shaft''s drive links.
 18. The apparatus claimed in claim 17 wherein: each bag engaging surface has a bead for engaging and holding the expanded mouth of a bag on the fingers.
 19. The apparatus claimed in claim 17 wherein each bag engaging surface has a beAd for engaging and holding the expanded mouth of a bag on the fingers, the beads in aggregate in the expanded position being on the circumference of a circle the center of which is the central axis.
 20. The apparatus claimed in claim 19 wherein each of the fingers has an inner surface which generally faces and parallels the central axis, the inner surfaces having a concave curvature of about the same as the curvature of the outside of a container body.
 21. An apparatus for attaching a flexible bag to a right cylindrical container body comprising: a. a base; b. a plurality of individual fingers disposed on the base for movement both ways between an expanded position and a contracted position, each of the fingers in its expanded position presenting an outer, bag engaging surface which cooperates with the bag engaging surfaces of the other fingers to define a surface array falling substantially on the surface of an imaginary right cylinder, the cylindrical array being for holding the expanded mouth of the bag for subsequent placement over the end of the container body, the fingers in their expanded position also presenting a passage for receipt of a container body within the fingers, the fingers in their contracted position presenting a generally elliptical array, the periphery of which is substantially less than the periphery of the bag engaging surfaces in their expanded position, the limited periphery elliptical array being to facilitate the receipt of the mouth of the bag over the fingers; and c. means for expanding and contracting the fingers between their expanded and contracted positions. 